It's just that ASan detects errors on a best effort basis, and it's
harder to detect a buffer overflow past the buffer's redzone.
On the other hand, such errors are quite rare.
On Tue, May 2, 2017 at 3:34 PM, Aayushi Agrawal <aayushigr...@gmail.com> wrote:
> So is this a kind of issue which is not handled by address sanitizer ?
>
> On 02-May-2017 5:45 pm, "'Alexander Potapenko' via address-sanitizer"
> <address-sanitizer@googlegroups.com> wrote:
>>
>> Most certainly the access to global_array[200] ends up touching a
>> valid location in g[], and the access to g[200] lands somewhere in a
>> region that has a shadow value of 0.
>> Unfortunately ASan can only detect a buffer overflow if the memory
>> access touches unaddressable memory (i.e. that with non-zero shadow).
>>
>> On Tue, May 2, 2017 at 2:09 PM, Aayushi Agrawal <aayushigr...@gmail.com>
>> wrote:
>> > Hello
>> >
>> > Here is code snippet -
>> >
>> > int global_array[101] = {-1};
>> > char g[101] = {-2};
>> >
>> > int main(int argc, char **argv) {
>> > global_array[atoi(argv[1])] = 70;
>> > g[atoi(argv[1])] = 'c';
>> >
>> > }
>> >
>> > If I compile it with clang , address sanitizer and no other flags used
>> > then
>> > for input as "101" it gives ASAN buffer overflow message but input as
>> > "200"
>> > does not show any buffer overflow why ?
>> >
>> >
>> > Aayushi
>> >
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>>
>> --
>> Alexander Potapenko
>> Software Engineer
>>
>> Google Germany GmbH
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